Bipole HVDC Current Sharing via Converter Phase Angle Control
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Solution Overview
Problem
In high voltage direct current (HVDC) power transmission networks, existing bipole power transmission schemes face challenges in efficiently managing DC current distribution between transmission conduits, leading to increased power transmission losses and maintenance needs, particularly in long-distance transmissions.
Innovation Solution
A bipole power transmission scheme with a converter station controller that adjusts the operating phase angles of AC voltages presented to a point of common coupling, allowing for controlled distribution of DC current between transmission conduits, thereby optimizing power transfer and reducing losses by altering the share of DC current carried by each conduit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If DC current distribution between transmission conduits is not controlled, then the system operates with fixed current distribution, but power transmission losses increase and maintenance needs increase
Solution Approach 1:
The patent changes the operating phase angle parameter of AC voltages at the point of common coupling to control DC current distribution. By adjusting the phase angle of AC voltages from first and second power converters, the system optimizes the share of DC current carried by each transmission conduit, thereby minimizing power transmission losses.
Solution Approach 2:
The converter station controller implements closed-loop control by continuously monitoring DC current distribution and adjusting the operating phase angles accordingly. The controller instructs power converter controllers to modify phase angles in opposite directions based on measured current distribution, creating a feedback mechanism that optimizes power transmission efficiency.
2Loss of energy
If DC current distribution is optimized through phase angle adjustment, then power transmission losses are reduced, but the control and measurement complexity increases
Solution Approach 1:
The converter station controller acts as an intermediary that coordinates between multiple power converter controllers. It processes measurements of DC current distribution and generates coordinated phase angle adjustment instructions, simplifying the overall control complexity by centralizing the decision-making logic while distributing the execution across multiple converters.
3Productivity
If the share of DC current carried by each conduit is altered, then power transmission efficiency improves, but the stability of power transfer may be affected
Solution Approach 1:
The system dynamically adjusts the operating phase angles of AC voltages to optimize DC current distribution in real-time. The converter station controller continuously monitors current distribution and modifies phase angles in opposite directions for different converters, enabling adaptive optimization of power transfer efficiency while maintaining system stability through coordinated control.
Data Source
AI summary
A bipole power transmission scheme includes a first converter station that is positioned, in-use, remote from a second converter station. First and second transmission conduits and a return conduit interconnect, in-use, the first converter station with the second converter station and thereby permit the transfer of power between the first and second converter stations. The first converter station includes a first power converter, a second power converter, and a converter station controller.